In recent years, use of mobile communications devices for voice telephone services, email or text messaging services and even multi-media service has become commonplace, among mobile professionals and throughout the more general consumer population. Mobile service provided through public cellular or PCS (personal communication service) type networks, particularly for voice telephone service, has become virtually ubiquitous across much of the world. In the USA, for example, competing public networks today provide mobile communications services covering most if not all of the geographic area of the country.
In addition to public networks, similar wireless technologies have provided relatively small scale networks for enterprise applications, typically offering wireless service analogous to private branch exchange (PBX) type service. Such a smaller scale private system includes several base stations, similar to but scaled down from those used in the public networks, in combination with a private circuit switch or more recently an Internet Protocol (IP) router or network, for providing communications between devices and with external networks. U.S. Pat. No. 6,970,719 to McConnell et al. and US application publication no. 2005/0059390 to Sayers et al. disclose examples of such private wireless cell phone networks. Although sometimes referred to as an “indoor cellular network” or “indoor system,” such enterprise systems need not be literally indoors and for example may offer coverage across an entire campus area. Alternatively, such an enterprise cellular communication system may be referred to as a “pico-cell” system, with the outdoor public cellular communication system covering a wider area being referred to as a “macro-cell” system.
As broadband IP connectivity to homes and offices has become more common, and the speeds of packet-switched communications equipment and the speed of processors have increased, a variety of applications have emerged that utilize IP packet transport as an alternative bearer for voice communications. Generally, such applications are referred to as voice-over-packet services, however, the common forms based on Internet Protocol (IP) are referred to as “Voice over IP” or “VoIP” services. Although originally developed for wireline network transport through the Internet and through wireline intranets, VoIP services are now migrating to the wireless domain. Pico cell systems, which use IP routing or frame switching for IP transport, utilize VoIP technology to support the voice services.
As an extension of these developments/deployments into the customer premises, particularly for residential or small business applications, equipment manufacturers have recently begun offering “femto” cell devices, e.g. for home installation. A “femto” cell system is a base transceiver system (BTS) forming a compact base station. In most recent examples, such compact base stations are equipped with VoIP capability and an IP interface, for example, for connection to a digital subscriber line (DSL) modem or to a cable modem. One such unit in a home or small business, for example, would allow mobile station users in the premises to make and receive calls via the existing broadband wireline service from the customer's Internet Service Provider (ISP), without consuming air-time minutes for wireless service that otherwise would use their public carrier's network.
It has been suggested that the deployment of femto cells will be particularly advantageous to a carrier as a way to improve service of the carrier's macro network in customer premises locations where the macro network service is less than optimum. For example, if a mobile station user may have weak coverage at his or her residence, installation of femto BTS in the home effectively extends macro network coverage into the home in a manner that substantially improves the customer's experience using the carrier's network.
At present, plans therefore are for the carrier(s) to distribute (sell or lease) the femto cell equipment to their public network customers. The femto cell is intended to work with a regular mobile station. To the mobile station, the BTS of such a femto cell appears like a normal base station of the public network. Deployment of femto cells, particularly in large numbers of customer premises, requires coordination with networks of the applicable public carriers, which raises issues for such a carrier.
Femto BTS devices are strategic products to allow a carrier to enhance network coverage by providing cellular coverage inside the customer premises, which are designed to be deployed and redeployed at any time. Despite its size, the femto BTS has almost all the salient features of a macro BTS and raises similar concerns regarding configuration for radio frequency (RF) operation. If treated in a manner analogous to introducing a new macro BTS into a network, comprehensive provisioning would be needed with respect to each new or redeployed femto cell. Some of the key RF parameters that would need to be provisioned are: RF channel assignment; PN assignment; Power; Updating the neighbor lists of all neighboring macro and femto BTS's, femto cell identifications such as SID/NID information, etc. Imagine introducing customer premises femto BTS products where the quantity, location, time of introduction are all indeterminate and can change at any time—the effort on the network engineers' part to provision these devices and to provision aspects of the macro network in relation to these devices would be enormous.
Provisioning of the femto cell and surrounding network in the same manner as for new macro cells therefore is not practical. However, the femto cell equipment does need to be configured, and the mobile stations do need to have sufficient knowledge of the femto cell configuration to allow the mobile stations to effectively access the femto cells. As a commercial matter, the service provided to the customer should appear seamless—virtually no different when receiving service through the femto cell than when receiving service through a macro cell BTS. The femto BTS devices operate as an underlay system to the macro network. For customers to widely accept such an underlay network the mobile stations should be able to move between the macro network and these devices seamlessly. Since the CDMA femto BTS is a new product in development, there is currently no known working deployment method within a macro network that addresses such provisioning or seamless service needs.
Hence, a strategy to permit seamless access to the femto cells for macro network mobile stations is needed that allows for a simple flexible deployment, with as much standardized configuration of the BTS equipment as possible, so as to not require extensive individualized provisioning in relation to each femto BTS.